做Redis的Cluster集群的时候，在执行gem install redis时，提示如下错误：

gem install redis

ERROR: Error installing redis:

redis requires Ruby version >= 2.2.2.

CentOS7 yum库中ruby的版本支持到 2.0.0，可gem 安装redis需要最低是2.2.2，采用rvm来更新ruby：

1、安装RVM(具体命令可以查看官网，Ruby官网地址 和 Ruby官网安装教程)：

复制代码

//具体RVM安装命令地址：http://rvm.io/

[root@linux ~]# gpg --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3 7D2BAF1CF37B13E2069D6956105BD0E739499BDB

[root@linux ~]# curl -sSL https://get.rvm.io | bash -s stable

[root@linux ~]# find / -name rvm -print

复制代码后执行结果

/usr/local/rvm

/usr/local/rvm/src/rvm

/usr/local/rvm/src/rvm/bin/rvm

/usr/local/rvm/src/rvm/lib/rvm

/usr/local/rvm/src/rvm/scripts/rvm

/usr/local/rvm/bin/rvm

/usr/local/rvm/lib/rvm

/usr/local/rvm/scripts/rvm

[root@linux ~]# source /usr/local/rvm/scripts/rvm

2、查看rvm库中已知的ruby版本：

[root@linux ~]# rvm list known

MRI Rubies

[ruby-]1.8.6[-p420]

[ruby-]1.8.7[-head] # security released on head

[ruby-]1.9.1[-p431]

[ruby-]1.9.2[-p330]

[ruby-]1.9.3[-p551]

[ruby-]2.0.0[-p648]

[ruby-]2.1[.10]

[ruby-]2.2[.7]

[ruby-]2.3[.4]

[ruby-]2.4[.1]

ruby-head

….

3、安装一个ruby版本：

[root@linux ~]# rvm install 2.4.1

Searching for binary rubies, this might take some time.

Found remote file https://rvm_io.global.ssl.fastly.net/binaries/centos/7/x86_64/ruby-2.4.1.tar.bz2

Checking requirements for centos.

Requirements installation successful.

ruby-2.4.1 - #configure

ruby-2.4.1 - #download

% Total % Received % Xferd Average Speed Time Time Time Current

Dload Upload Total Spent Left Speed

100 14.1M 100 14.1M 0 0 97k 0 0:02:27 0:02:27 --:--:-- 159k

No checksum for downloaded archive, recording checksum in user configuration.

ruby-2.4.1 - #validate archive

ruby-2.4.1 - #extract

ruby-2.4.1 - #validate binary

ruby-2.4.1 - #setup

ruby-2.4.1 - #gemset created /usr/local/rvm/gems/ruby-2.4.1@global

ruby-2.4.1 - #importing gemset /usr/local/rvm/gemsets/global.gems..............................

ruby-2.4.1 - #generating global wrappers........

ruby-2.4.1 - #gemset created /usr/local/rvm/gems/ruby-2.4.1

ruby-2.4.1 - #importing gemsetfile /usr/local/rvm/gemsets/default.gems evaluated to empty gem list

ruby-2.4.1 - #generating default wrappers........

4、使用一个ruby版本：

[root@linux ~]# rvm use 2.4.1

Using /usr/local/rvm/gems/ruby-2.4.1

5、设置默认版本：(设置ruby2.4.1为默认的ruby，因为还安装有1.8.3)

[root@linux ~]# rvm use 2.4.1 --default

Using /usr/local/rvm/gems/ruby-2.4.1

6、卸载一个已知版本：

[root@linux ~]# rvm remove 2.3.4

7、查看ruby版本：

[root@linux ~]# ruby --version

ruby 2.4.1p111 (2017-03-22 revision 58053) [x86_64-linux]

8、安装redis：

[root@linux ~]# gem install redis

Fetching: redis-4.0.1.gem (100%)

Successfully installed redis-4.0.1

Parsing documentation for redis-4.0.1

Installing ri documentation for redis-4.0.1

Done installing documentation for redis after 3 seconds

1 gem installed